Hydrocarbon conversion



May 6, 1969 J. w. oAvlsoN HYDROCARBON CONVERSION Filed Feb. '7, 1966 INVENTOR J.W. DAVISON T TORNEVS United States Patent O 3,442,970HYDROCARBON CONVERSION Joseph W. Davison, Bartlesville, Okla., assignorto Phillips Petroleum Company, a corporation of Delaware Filed Feb. 7,1966, Ser. No. 525,523 Int. Cl. C07c 3/20, 3/62, 11/04 U.S. Cl.260-683.15 1 Claim ABSTRACT OF THE DISCLOSURE This invention relates tohydrocarbon conversion. In one aspect, the invention relates to anintegrated process for propylene disproportionation and the productionof alpha-olens. In another aspect, the invention relates t convertinglower molecular wei-ght olens to Ihigher Vmolecular weight olefins. Inanother aspect, the invention relates to the production of butene andhigher molecular weight oleins from propylene.

An object of my invention is to disproportionate propylene, polymerizeproduced ethylene to produce long chain alpha-olefins and recover buteneproduced by the dis'proportionation.

Another object of my invention is to provide a highly ecient integratedpropylene disproportionation and alpha-olefin producing process.

Othe-r aspects, objects and the advantages of my invention are apparentin the written description, the drawing and the claims.

According to my invention, propylene is disproportionated, at least aportion of the ethylene produced from the disproportionation polymerizedto produce alphaolens, the efuent of the ethylene polymerization ashedin a high pressure flash zone in which butene also produced by thedisproportionation is used as a recycle. A portion of the ethyleneproduced in the disproportionation step along with unreacted propylenecan be recycled to the disproportionation step, while a portion of thebutene produced can be recovered as a product, and ethylene and butenefrom the high pressure flash zone recycled to the separation step forthe disproportionation efuent.

In this application, disproportionation is used to mean the conversionof a hydorcarbon into similar hydrocarbons of higher and lower numberedcarbon atoms per molecule. Such an operation is used in many instances.For example, a more plentiful hydrocarbon can be converted to a lessplentiful and, therefore, more valuable hydrocarbon. When propylene isdisproportionated, approximately equimolar quantities of ethylene andbutenes are produced.

Disproportionation can be accomplished using any catalyst suitable forthe reaction including, for example, a catalyst comprising molybdenumoxide and aluminum oxide, a catalyst comprising tungsten oxide andsilica, a catalyst comprising molybdenum hexacarbonyl or tungstenhexacarbonyl and alumina, etc. Operative and preferred conditions fordisproportionation vary with the catalyst selected. Details of somesuitable disproportionation processes are given in copending applicationSer. No. 307,371, Heckelsberg, led Sept. 9, 1963 and now abandoned; Ser.No. 312,209, Banks, tiled Sept. 27, 1963,

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now Patent No. 3,261,879; Ser. No. 336,624, Heckelsberg, iiled Ian. 9,1964, now Patent No. 3,340,322; and Ser. No. 94,996, Banks, tiled Mar.13, 1961.

Alpha olefins can be polymerized to produce higher molecular weightalpha oleiins by contacting a lower molecular weight olefin with analuminum alkyl such as aluminum triethyl at suitable operatingconditions. When the lower molecular weight olefin is ethylene, astraight chain alpha olen is produced. The polymerization reaction canbe conducted continuously by maintaining suitable conditions includingthe proper mol ratio of olens to aluminum alkyl and conditions oftemperature, pressure, etc., such that the higher boiling olens areproduced.

In the drawing, propylene is fed to disproportionation reactor 11through pipe 12. The etliuent from reactor 11 is passed to a separator13 through pipe 14. In separator 13 a separation is made whereby astream comprising predominantly ethylene is removed overhead throughpipe 16, a stream comprising substantially all of the unreactedpropylene together with a portion of the produced ethylene is recycledthrough pipe 17 to inlet pipe 12 and a bottoms product comprisingpredominantly butenes is removed through pipe 18. The ethylene producedthrough pipe 16 is mixed with a suitable catalyst such as, for example,triethylaluminum, which enters through pipe 19 and the reaction mixturepassed through pipe 21 to alpha olelin reactor 22. The effluent fromreactor 22 is passed through pipe 23 to a high pressure ash vessel 24.From vessel 24 a bottoms stream is removed containing C6 and heavieralpha olens. Ethylene and butene are removed through pipe 27 `andreturned to separator 13. Reflux is provided for the upper trays of ashvessel 24 through pipe 28, while excess butenes are removed through pipe29 as a butenes product which can be used, for example, in a butenedehydrogenation operation to produce butadiene. If some ethyleneproduction is desired, it can be removed from pipe 16 through pipe 31 byopening valve 32.

Although not shown, the combination of steps of this invention areunitized to conserve heat, materials and equipment by the use ofsuitably located heat exchangers, separation stages, and recyclestreams. Other equipment and process steps can be utilized as desired ornecessary including, for example, pumps, valves, separators, heaters,coolers, catalyst separators, or other separation and recycle steps,etc. Any suitable design can be used for the various elements of thedisclosed apparatus. For example, separator 13 suitably is a fractionaldistillation column. Conditions are selected within those suitable forthe disproportionation and alpha olen reaction and for the separation inseparator 13. The high pressure flash vessel 24- preferably ismaintained at a pressure of 450 p.s.1.g.

In an example according to my invention, reactor 11 is maintained at atemperature of 800 F. and 425 p.s.i.g., reactor 22 is maintained at 425F. and 8,500 p.s.i.g. The eluent from reactor 22 is flashedadiabatically to a pressure of 450 p.s.i.g. in ash vessel 24. Theeffluent from -reactor 11 and the overhead from flash vessel 24 are fedto separator 13 as shown. Separator 13 is operated at a pressure of 425p.s.i.g. with a temperature of F. at the top and 280 F. at the bottom.

The compositions of the flow streams at various points in the processare given in the following table, in which the numbers correspond withthe circled numbers in the drawing.

It will be noted that no reflux to flash vessel 24 was utilized in thisexample. In other specific operations, such reflux may be desirable ornecessary and can be supplied in suitable amounts for proper operationof flash vessel 24.

TABLE-COMPOSITION IN LBJLB. OF PROPYLENE ENTERING REACTOR 11 Components1 2 3 4 5 6 7* 8 9 10 11 12 13 14 15 Ethylene 0 064 Propylene. 11000Tetradecene Hexadecene and heavier ole- *No ethylene removed.

Reasonable variation and modication are possible in a high pressureflash zone and recovering alpha within the scope of my invention whichsets forth an 15 oleflns therefrom; integrated process for propylenedisproportionation and returning C4 and lighter oiens from said highpressure ethylene polymerization to produce alpha olens. ash Zone tosaid separation zone;

I claim: and reliuxing said high pressure flash zone with a 1. A processwhich comprises: portion of the butene of said third stream.

disproportionating propylene to produce ethylene and 20 butene;References Cited separating the eiuent from the disproportionationUNITED STATES PATENTS step in a separation Zone to produce a rst streamcomprising ethylene with substantially no heavier olens, a second streamcomprising propylene and 25 a small amount of ethylene, and a thirdstream comprising butene; PAUL M. COUGHLAN, JR., Przmary Examzner.polymerizing at least a portion of said ethylene in said C E SPRESSER,Assistant Examiner,

first stream to produce alpha oleins having 12 t0 20 carbon atoms permolecule; 30 U.S. Cl. X.R. flashing the product of said ethylenepolymerization 260-683 '2,198,937 4/1940 Frey et al. 260-683.153,330,882 7/1967 Albright 26o-683.15

